This invention relates to storage batteries having a gelled acid electrolyte and to a method for making such batteries.
Rechargeable batteries for vehicles and other uses comprise one or more cells having alternating positive and negative electrodes and an electrolyte. In a vehicle battery having sulfuric acid as the electrolyte, the acid may be converted to a colloid to provide a sealed battery. Conventional gel batteries include a microporous barrier between adjacent lead electrodes. Cooled battery acid is first mixed with a gelling agent, such as fumed silica, and is poured into the electrolyte cavities of the battery. The battery is then sealed and charged, with the acid being converted into a stable gel form.
While gel batteries described above enjoy widespread use, problems may arise during manufacture. Inadequate mixing of the gelling agent with the acid or premature gelling of the mixture may cause the formation of voids or air pockets in the electrolyte cavities of the battery. Also, inclusion of sufficient amounts of silica to form a stable gel, in the order of eight percent by weight of battery acid, in effect reduces the amount of available electrolyte in the battery.